Yet in recent months and, particularly, in the wake of Israel's electoral lurch to the right last Tuesday, a number of Israelis and Palestinians are warning that the two-state solution is in its death throes. Increasingly observers foresee a "one-state solution" imposing itself – something many moderates on both sides say would be disastrous and would mean instability in the region for decades to come.

Even Libyan President Muammar Qadafi says the two-state solution is no longer an option and that only a single state – with Israelis and Palestinians living together in harmony – remains as a viable solution to the decades-old conflict.

The two sides give different reasons to explain why the chances of reaching a two-state solution are evaporating.

On the Palestinian side, the explanation is as simple as a map showing the steady encroachment by Israel into Palestinian lands in the form of settlements in the occupied West Bank. Between the settlements and the Israeli wall shutting off Palestinian movement and commerce, the possibility of a viable state has been nipped in the bud, Mr. Barghouti says.

And on the Israeli side, support for the two-state solution has withered as Israelis have become convinced that they have no viable partner among the Palestinians with whom to negotiate a two-state solution.

Mr. Pinkas says that recently a number of Israeli leaders, "myself included, warned [former secretary of State] Condoleezza Rice that while the two-state solution is a wonderful idea, it is losing its appeal and becoming less and less viable as Israelis and Palestinians drift apart."

But the parties on the ground see little prospect for progress. In Israel, former prime minister and Likud leader Benjamin Netanyahu, who is expected to be called on to try to form a government, refuses to hear of any settlement freeze but calls for the destruction of the Hamas leadership that controls Gaza. Palestinian leaders say they are awaiting Mr. Mitchell's order to Israel to freeze its settlement building – in line with the conclusions of a report Mitchell delivered in 2001 on the causes of Palestinian violence.

Mitchell is expected to make his second trip to the region as Mr. Obama's envoy at the end of the month. But political realities in the US seem to offer little reason to believe such an order will be forthcoming.

Israelis who see the one-state solution as a disaster for Israel give a one-word explanation: demographics. They note that as early as 2017, Palestinian Arabs both inside Israel proper and in the occupied territories will outnumber Israeli Jews. That, they say, would spell the end of the Jewish state.

For some moderate Israelis like Pinkas, the one-state solution is anathema and the two-state solution is now so distant at best that the only option is a "shelving" of all final-status negotiations while a viable Palestinian partner with functioning institutions is developed with international assistance.

But Barghouti says that option condemns Israel to its current course of "occupation, racism, and apartheid." The only outcome, he says, will be more unrest.

What's needed is a sign of hope to Palestinians, he says, in the form of an order from Mr. Obama and Mitchell that Israel freeze its settlement activity or face a loss of US assistance.

"If that doesn't happen," he says, "they can kiss the two-state solution good-bye."